Speaker
Description
Synchrotron based Low Energy X-ray Fluorescence (XRF) spectroscopy is one of the most widely used non-destructive techniques for elemental analysis in many fields; from biomedical to electrochemical. Even if XRF emission is an isotropic phenomenon, the specimen inhomogeneities may exhibit angular dependence. Despite the modern understanding of the technique, angular dependence artifacts remain an issue especially when using micro- or nano-X-ray beams and detectors located at small angles with respect to the sample surface. The more perpendicular the incident beam is with respect to the sample surface, the deeper the incident photons will penetrate inside the specimen. The higher the angle of incidence, the more the analysis will be limited to the sample surface. This is due to the progressive absorption of incident photons when traveling inside the sample. Although the angular dependence may be an advantage in some cases, when analyzing inhomogeneous samples with non-flat surfaces such as biological specimens with micro- or nano-beams, the sample topography and surface roughness play an important role and may cause misleading interpretations if not carefully taken into account.
This work presents certain relevant findings from a series of beamtime experiments in the spectromicroscopy synchrotron beamline TwinMic [1] in Elettra Sinctrotrone Trieste, Italy. The latest of these experiments use a novel SDD detector system [2] with a multi-element detection layout suitable for the topographical methods we have developed [3].
Figure 1. XRF maps showing Aluminum acquired from diametrically opposed detectors exhibiting angular detection artifacts and shadowing.
[1] A. Gianoncelli et al., Synchrotron Radiation, vol. 23, 2016
[2] J. Bufon et al., X-Ray Spectrometry, vol. 46, 2017
[3] F. Billè et al., Spectrochimica Acta B, vol. 122, 2016
